Synthesis of Multifunctional Metal-Organic Frameworks and Tuning the Functionalities by Organic Pendant of Ligand

A series of multifunctional metal-organic frameworks (MOFs), SNU-170 ~ SNU-176, have been synthesized by using the ligands, in which various functional pendant such as -NH2, -SMe, -OMe, -OEt, -OPr, and –OBu is attached to the phenyl ring of 4-(2-carboxyvinyl)benzoic acid. The MOFs are isostructural but the interpenetration depends on the pendant group of the ligand. The MOFs exhibit high adsorption capacities of H2, CO2, and CH4 gases, ligand-based photoluminescence, and chemical sensing abilities, all being affected by the pendant group. All of the as-synthesized MOFs can sense nitro-aromatics by the luminescence quenching, and some of the activated MOFs can sense the type of solvents by the altered emission maxima with enhanced intensity. In particular, SNU-176 synthesized from a mixture of two different ligands with –SMe and -OMe pendants shows higher gas adsorption capacities than the MOFs synthesized from the individual ligands (SNU-171 and SNU-172). It also shows the ability to differentiate nitrobenzene (NB) and 2,4-dinitrotoluene (DNT) unlike the MOFs constructed of the single ligands.